Extraction of tin from ores, alloys, scrap or the like



Patented Get. 6, 1931 warren STATES PATENT OFFICE LEON LAMY, or ammcy, EUGENE mrnrnu, or rams, Am: LEON caexuox, or

mmmenmn, amen, assmnoas 'I'O socmrn nnLnc'rno-cgImE, :o'nnnc'rnomnrmnnem m: nus ncmams nnnc'rmeuns nuemn, or rams, FRANCE, A

CORPORATION OF FRANCE EXTRACTION OF TIN FROM ORES, ALLOYS, SCRAP OR THE LIKE Ho Drawing. Application filed January 24, 1930, Serial No. 428,280, and in France June 22, 192% This invention relates to improvements in the extraction of tin from ores, alloys, slag, scrap or the like which also contain iron.

It has already been proposed in U. S. Patent No. 1,518,742, ranted Dec. 9, 1924 to Lon Lamy, one pf t e present applicants, to recover tin in a commercial form from such materials by causing a substance such 10 as silicon, ferro-silicon, a metal, metalloid or alloy, having the property of forming an alloy with the iron, to act on the mineral or alloy or the like, at any period of the reduction or refining operation. 1

This process has given excellent results and permits of an effective recovery of the tin in a condition practically free from iron. In the use of silicon or ferro-silicon in this process however it was foundthat the ferrosilicon produced contained a small proportion of tin varying between 1.5 and 6% of the iron content of the ore or the like and about 0.75 to 15% of the tin originally contained in the material. On this account not only was a portion of the tin unrecovered but also the ferro-silicon obtained was unfit for use especially in the metallurgy of iron. In accordance with the present invention the above process is improved, the cost reduced and the yield increased. Practically the whole ofthe tin is recovered from the ore or the like in a commercial form and a ferro-silicon is obtained practically free from tin and accordingly suitable for use, especially in iron metallurgy. g

The improved process Of manufacture of this iron is by addingto the initial charge of ore or the like a quantity of silicon, as such or in the form of ferro-silicon or the like, such that the ferro-silicon produced is formed as a binary alloy Fe-Si, which is substantially unattacked by hydrochloric acid for example and in which any tin is contained in the free state above its solidification point. A ferro-silicon alloy containing at least 30% of silicon possesses these latter properties.

By regulating the course of the process of treatment described in U. S. Patent No.

1,518,742, referred to above in such a way as to obtain a ferro-silicon containing 30% 33%, this ferro-silicon product still contains tin but since this tin is in the free state it is possible to separate it and to recover it almost completely either by physical means (cooling and separation by difierence of density) or by chemical means for example treatment with hydrochloric acid or an acid solution of stannous chloride whereby iron and silicon are practically unattacked but almost the whole of the tin is dissolved.

In this manner a ferro-silicon is finally obtained which can be utilized in iron metallurgy and practically the whole of the tin is recovered in a commercial form.

It is to be understood that the alloy Fe-Si with 33% Si, indicated above, is only given by way of example which is in no way limiting since other iron silicon compounds containing at least 30% of silicon may be obtained which satisfy the same conditions of not being attacked by hydrochloric acid and containing the tin in the free state.

On the other hand, while it is necessary to the attainment of the specified conditions Having now particularly described and ascertained the nature of our said invention and in which manner the same is to be performed we declare that what we claim is:

1. Process for the extraction of tin from materials containing tin and iron, consisting in adding to the material under treatment during the operation of reduction or refining siliconin determined quantity to form with the iron content a ferro-silicon compound which contains a minimum of 30% silicon.

2. Process for the extraction of tin from materials containing tin and iron, consisting in adding to the material under treatment during the operation of reduction or refining silicon in determined quantity to form with the iron content a ferro-silicon compound which contains from 30% to 33% silicon.

3. Process for the extraction of tin from materials containing tin and iron, consisting in adding to the material under treatment during the operation of reduction or refinin silicon in determined quantity to form wit the iron content a ferro-silicon compound which contains from 30% to 33% silicon and then cooling the mass and separating the free tin contained therein.

4. Process for the extraction of. tin from materials containing tin and iron, consisting in adding to the material under treatment during the operation of reduction or refinin silicon in determined quantity to form wit the iron content a ferro-silicon compound which contains from 30% to 33% silicon and then cooling the mass and separating the free tin contained therein by difference of density, '5. Process for the extraction of tin from materials containing tin and iron, consisting in adding to the material under treatment during the operation of reduction or refining silicon in determined quantity to form with the iron content a ferro-silicon compound which contains a minimum of 30% silicon and then treating the mass with a solvent of tin which does not attack iron or silicon.

In testimony whereof we have signed this specification. LEON LAMY.

EUGENE MATHIEU LEON GAGNAUX. 

